The present invention relates generally to integrated circuit packaging and more specifically to an Ultra Thin Ball Grid Array (UTBGA) integrated circuit package and a method of making the package which uses a temporary supporting substrate carrier to support the components of the package during the assembly of the package.
In the field of integrated circuit packaging, the cost and size of the overall package are major concerns. Any reduction in the cost of producing the package or reduction in the size or thickness of the package can provide a significant commercial advantage. To this end, the packaging of integrated circuits is continuously being improved to provide more cost effective designs and methods of producing integrated circuit packages.
There are currently several types of prior an Ball Grid Array (BGA) packages currently available. These prior an types include the Plastic Ball Grid Array (PBGA), the Ceramic Ball Grid Array (CBGA), and the Tape Ball Grid Array (TBGA). The PBGA and the TBGA are the thinnest ball grid array packages currently available. Referring to FIG. 1, a typical prior art PBGA integrated circuit package generally indicated by reference numeral 10 will be described. Prior art package 10 includes a dielectric substrate 12 an integrated circuit die 14, an array of bonding wires 16, an encapsulating material 18, and an array of contacts or solder balls 20.
As shown in FIG. 1, substrate 12 has a top surface 22, a bottom surface 24, a plurality of electrically conductive terminal pads 26 on the top surface 22 of substrate 12, a plurality of contact terminal pads 28 on the bottom surface 24 of substrate 12, and a plurality of electrically conductive traces (not shown). Each of the electrically conductive traces interconnects a respective one of terminal pads 26 on the top of substrate 12 to an associated contact terminal pad 28 on the bottom of substrate 12. Substrate 12 is made from a rigid material capable of supporting the other components of the package during the assembly of the package. Integrated circuit die 14 has a top surface 30, a bottom surface 32, and includes a plurality of input/output terminals 34 on its top surface 30. Each of the bonding wires 16 electrically connect a respective one of terminal pads 34 to an associated terminal pad 26 on the top surface of substrate 12. Encapsulating material 18 encapsulates integrated circuit die 14, at least the top surface of substrate 12, and bonding wires 16. Contacts or solder balls 20 are attached to associated contact terminal pads 28 thereby allowing external electrical elements to be electrically connected to integrated circuit die 14. This arrangement represents the typical prior art PBGA integrated circuit package.
The present invention provides a novel method of producing an Ultra Thin Ball Grid Array which can result in a PBGA package thinner than possible using prior art methods of producing BGA packages. This is accomplished by minimizing or eliminating the thickness of the substrate (i.e. substrate 12 of the prior art embodiment described above) and instead using a temporary supporting substrate or carrier to support the other components of an integrated circuit package during the assembly of the package. As will be described in more detail hereinafter, this novel method also provides a less expensive package by reducing the overall substrate cost by maximizing the substrate panel utilization as well as increase the substrate yield.